WellPoint reported higher first-quarter profit on Wednesday, helped by gains in membership.
Net income rose to $783.1 million, or $1.26 per share, from $731.8 million, or $1.09 per share, a year earlier.
Analysts on average expected $1.26 a share, according to Reuters Estimates.
Through acquisitions, WellPoint has grown into the largest U.S. health insurer by membership, but investors are worried that the market for employer-based health-plan enrollment is flattening and that competition will force insurers to cut their pricing.
WellPoint shares have climbed about 5% this year, outpacing the stock performance of rivals UnitedHealth Group and Aetna .